People at Artscape stared at the group of dancers in a small pocket park. A man in a tucked-in checkered shirt twirled his fingers, a woman in a red bandana danced the hula and a boy in an Outkast T-shirt moved his hips.

Yet there was no music in the air.

That was the magic of the Silent Disco, one of the exhibits at the city's 33rd annual free arts festival. Dancers inside Pearlstone Park at Cathedral and Preston streets wore wireless headphones that pumped house and club music into their ears.

The sight of strange twirling silence was enough to lure Jon George, 21, and a friend, Nicole Ramlogan, 24, both from Baltimore, to give it a try.

"I like that people who are passing by don't know what we're dancing to," Ramlogen said.

Within the park, two DJs were simultaneously pumping beats. One of them, Neal Conway, was playing "soulful house," soul and funk music. Conway said it was his first time participating in a silent disco, which he called a "unique visual experience." He enjoyed looking among the crowd and trying to guess who was listening to his music and who was listening to that provided by the other DJ.

The experience Sunday was one of many exhibits, food stands and concert areas that were packed or steadily filling with people. Thanks to a comfortably warm and relatively sunny July day and later-than-normal hours, Artscape might outpace its typical attendance this year, organizers said.

"From my experience, [Saturday] was, if not the biggest, certainly one of the biggest days we've ever had," Bill Gilmore, executive director of the Baltimore Office of Promotion & the Arts, said Sunday. "It's all about fair-weather friends that came out."

Past festivals have drawn an average of about 350,000 people, Gilmore said. While this year's estimate won't be compiled for about another week, attendance is likely on track to exceed that, he said.

Temperatures that peaked in the low-80s helped and were definetely an improvement over last year's mid-90s. And the roster of expanded and ever-changing performing and visual arts proved a big draw, Gilmore said.

Other big attractions were the free contemporary dance and ballet performances at the Lyric, which have been at capacity, he said.

Many also flocked to "After Hours" on Friday and Saturday on North Charles Street. After vendors packed up at 9 p.m., DJs took over the Aerial Arts Arena and Station North Stage, and food and beverage vendors stayed open until 11 p.m. Artscape planners decided on the late-night event after receiving lots of requests.

"For the number of younger folks, 9 o'clock is pretty early, and we thought doing this on Charles Street was a good idea," Gilmore said. "It allowed the vendors and those who had worked all day to go home."